In May 2010 the United States National Science Foundation sponsored a two-day workshop to review the state-of-the-art and research challenges in photovoltaic (PV) manufacturing. This article summarizes the major conclusions and outcomes from this workshop, which was focused on identifying the science that needs to be done to help accelerate PV manufacturing. A significant portion of the article focuses on assessing the current status of and future opportunities in the major PV manufacturing technologies. These are solar cells based on crystalline silicon (c-Si), thin films of cadmium telluride (CdTe), thin films of copper indium gallium diselenide, and thin films of hydrogenated amorphous and nanocrystalline silicon. Current trends indicate that the cost per watt of c-Si and CdTe solar cells are being reduced to levels beyond the constraints commonly associated with these technologies. With a focus on TW/yr production capacity, the issue of material availability is discussed along with the emerging technologies of dye-sensitized solar cells and organic photovoltaics that are potentially less constrained by elemental abundance. Lastly, recommendations are made for research investment, with an emphasis on those areas that are expected to have cross-cutting impact.

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Semiconductor quantum dots (QDs) have recently been incorporated into consumer displays and lighting technologies. Now that these materials are being produced on industrial scales, it is important to investigate scalable synthetic methods and less toxic materials and chemistries. To achieve these goals, we have synthesized cadmium-free, visible light-emitting QDs using a microwave-assisted continuous flow reactor. After synthesis, the CuInS 2 QD cores underwent a near-complete Zn cation exchange reaction in a batch reactor, followed by the growth of a ZnS shell. Analysis of X-ray diffraction, transmission electron microscopy, and Raman spectroscopy data indicate that the crystal structure changes from CuInS 2 (chalcopyrite) to ZnS (zincblende) during the cation exchange reaction. Compositional analysis indicated that the core/shell QDs were *98 % ZnS, with Cu and In present at much lower concentrations. The photoluminescence (PL) peak position was blue shifted for longer cation exchange reactions, and it was found that the ZnS shell was necessary for improved PL stability.The synthesized QDs have a PL down conversion efficiency of *65 % when using a blue LED source.